In this study, flow cytometric analysis was used to evaluate the genetic stability of Passiflora cincinnata Mast. plants regenerated via primary and secondary somatic embryogenesis. Embryogenic calli obtained from culturing zygotic embryos on Murashige and Skoog (MS) medium containing 18.1 lM 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.4 lM benzyladenine (BA) were transferred to differentiation medium. Torpedo and cotyledonary embryos were obtained. These primary embryos were maintained on differentiation medium to generate secondary embryos. Conversion of primary and secondary embryos yielded 305 and 138 normal plants, respectively. Almost 90% of plantlets survived following acclimatization. Flow cytometric analysis revealed that seed-derived plants had on average 3.01 pg nuclear DNA (2C), and all plants, except for a single plant regenerated via primary embryogenesis, maintained their ploidy. This single plant contained more than twice the average DNA content: 6.21 pg (4C). Epidermal stomata of leaves of the tetraploid plant were larger but lower in density than those of diploid plants, indicating that stomatal characteristics are useful in distinguishing between diploid and tetraploid plants of passion fruit. In summary, the procedure we employed to regenerated P. cincinnata plants via somatic embryogenesis generated mostly genetically true-to-type plants.

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During the past decade, sweet sorghum (Sorghum bicolor Moench L.) has shown great potential for bioenergy production, especially biofuels. In this study, 223 recombinant inbred lines (RILs) derived from a cross between two sweet sorghum lines (Brandes × Wray) were evaluated in three trials. Single nucleotide polymorphisms (SNPs) derived from genotyping-by-sequencing of 272 RILs were used to build a high-density genetic map comprising 3,767 SNPs spanning 1,368.83 cM. Multi-trait multiple interval mapping (MT-MIM) was carried out to map quantitative trait loci (QTL) for eight bioenergy traits. A total of 33 QTLs were identified for flowering time, plant height, total soluble solids and sucrose (five QTLs each), fibers (four QTLs), and fresh biomass yield, juice extraction yield, and reducing sugars (three QTLs each). QTL hotspots were found on chromosomes 1, 3, 6, 9, and 10, in addition to other QTLs detected on chromosomes 4 and 8. We observed that 14 out of the 33 mapped QTLs were found in all three trials. Upon further development and validation in other crosses, the results provided by the present study have a great potential to be used in marker-assisted selection in sorghum breeding programs for biofuel production.

The Bowman-Birk (BBI) protease inhibitors can be used as source of sulfur amino acids, can regulate endogenous protease activity during seed germination and during the defense response of plants to pathogens. In soybean this family has not been fully described. The goal of this work was to characterize in silico and analyze the expression of the members of this family in soybean. We identified 11 potential BBI genes in the soybean genome. In each one of them at least a characteristic BBI conserved domain was detected in addition to a potential signal peptide. The sequences have been positioned in the soybean physical map and the promoter regions were analyzed with respect to known regulatory elements. Elements related to seed-specific expression and also to response to biotic and abiotic stresses have been identified. Based on the in silico analysis and also on quantitative RT-PCR data it was concluded that BBI-A, BBI-CII and BBI-DII are expressed specifically in the seed. The expression profiles of these three genes are similar along seed development. Their expressions reach a maximum in the intermediate stages and decrease as the seed matures. The BBI-DII transcripts are the most abundant ones followed by those of BBI-A and BBI-CII.

Spodoptera frugiperda is the most economically important maize pest in Brazil. There is little information about the genetic structure, using SSR markers, of S. frugiperda populations collected from maize crops. In this study, 21 SSR markers were used to evaluate the genetic diversity and population structure of S. frugiperda collected from distinct Brazilian geographical regions. Two hundred and twenty-seven alleles were recorded with an average of 10.76 per marker, and Polymorphic Information Content (PIC) values ranging from 0.242 to 0.933, with an average of 0.621, indicating a high discriminating power. The overall F ST , 0.061, indicated a moderate genetic differentiation among the S. frugiperda populations collected from maize, and the AMOVA showed that 87.36% of the genetic variation is within populations. The Mantel test showed significant correlation between genetic and geographic distances. The genetic data demonstrated that all individuals from the six sampling sites were structured as two sub-populations, being one of them composed only by the CL population, collected in the Rio Grande do Sul state. The knowledge about genetic diversity and population structure of S. frugiperda is important for the development of strategies for the insect pest management and monitoring systems, especially for the differentiated CL population.